package com.running.base.run.util;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * @create: 2019-05-09 14:18
 **/
public class AesUtil {

    private static final String AES_MODEL = "AES/CBC/NoPadding";
    private static final String ALGORITHM = "AES";

    /**
     * 加密用的Key 可以用26个字母和数字组成 使用AES-128-CBC加密模式，key需要为16字节
     */
    private static final String key = "pj7x89H$LuBI0437";
    private static final String iv = "Nrfb&91GUY80Gfgh";


    /**
     * @param data 明文
     * @return 密文
     * @Description AES算法加密明文
     */
    public static String encryptAES(String data) throws Exception {
        try {
            Cipher cipher = Cipher.getInstance(AES_MODEL);
            int blockSize = cipher.getBlockSize();
            byte[] dataBytes = data.getBytes();
            int plaintextLength = dataBytes.length;

            if (plaintextLength % blockSize != 0) {
                plaintextLength = plaintextLength + (blockSize - (plaintextLength % blockSize));
            }

            byte[] plaintext = new byte[plaintextLength];
            System.arraycopy(dataBytes, 0, plaintext, 0, dataBytes.length);

            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), ALGORITHM);
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());  // CBC模式，需要一个向量iv，可增加加密算法的强度

            cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
            byte[] encrypted = cipher.doFinal(plaintext);

            return AesUtil.encode(encrypted).trim(); // BASE64转码
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * @param data 密文
     * @return 明文
     * @Description AES算法解密密文
     */
    public static String decryptAES(String data) throws Exception {
        try {
            byte[] encrypted1 = AesUtil.decode(data);//先用base64解码

            Cipher cipher = Cipher.getInstance(AES_MODEL);
            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), ALGORITHM);
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());

            cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);
            byte[] original = cipher.doFinal(encrypted1);

            return new String(original).trim();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 编码
     *
     * @param byteArray
     * @return
     */
    private static String encode(byte[] byteArray) {
        return new String(new Base64().encode(byteArray));
    }

    /**
     * 解码
     *
     * @param base64EncodedString
     * @return
     */
    private static byte[] decode(String base64EncodedString) {
        return new Base64().decode(base64EncodedString);
    }


}
